Driven turbochargers are an improvement over normal turbochargers since driven turbochargers (super-turbochargers) are powered by more than just the exhaust gas turbine, which reduces turbo-lag in boosted engines. Driven turbochargers can also direct excess turbine power back to the engine to increase engine efficiency. One class of driven turbocharger utilizes a traction drive that interfaces with the turbo shaft to provide torque to and from the turbo shaft.